The present disclosure relates to catheter and guidewire systems. More particularly, it relates to catheter-based systems employing two or more guidewires to deliver to a therapeutic device to a patient.
A variety of different therapies can be delivered within the human body by catheter systems or devices. Therapeutic devices such as stents, stent grafts, endografts, filters, dilation balloons are but a few examples, and are conventionally delivered to a target site in a contracted or compressed state within a catheter. The device is typically loaded at a distal end of the catheter; once properly located, the catheter is proximally retracted and/or the device is distally advanced.
To aid in positioning of the distal end of the catheter within the body, typically a guidewire is first navigated to the treatment area. After the guidewire has been positioned, the catheter can be directed along or over the guidewire, bringing the distal end of the catheter to a desired position. In this regard, the catheter will form at least one lumen that slidably receives the guidewire. For many procedures, the catheter will provide two (or more lumens), with at least one of the lumens dedicated to the guidewire.
In addition to facilitating catheter placement, guidewires are also employed to achieve desired arrangement or deployment of the catheter-delivered device in some instances. For example, devices intended to branch across bodily vessel bifurcation (e.g., a bifurcated stent graft). In vessel bifurcations, a main vessel splits into two branch vessels. Implanting stents or stent grafts in bifurcations is particularly problematic because of the need to precisely locate the stent both longitudinally and radially in the bifurcation, for example to locate a side opening or branch of the stent graft to face and extend into the branching vessel. Such devices and corresponding methods of delivery require complicated manipulations and precise delivery to specific target locations. Where the stent graft or other device to be implanted provides multiple side openings (fenestrations) or branches each intended to face or be located within a separate branch vessel (e.g., an abdominal aortic aneurysm stent graft), the procedure is even more complicated. Oftentimes, multiple guidewires are required to properly align each opening with respect to a corresponding branch vessel.
Where a particular procedure benefits from the provision of multiple guidewires to effectuate alignment of the device to be implanted relative to the native anatomy, clinicians prefer that the multiple guidewires be delivered through a single catheter (as opposed to providing a separate catheter and access approach for each guidewire). While loading of the guidewires to the catheter or delivery sheath and subsequent delivery of the device over the guidewires once in place is in theory straightforward, problems may arise. In particular, due the tortuous delivery path presented by many procedures and/or the manipulations of the guidewires in order to achieve necessary vessel or side branch location, two or more of the guidewires oftentimes wrap or twist about one another. Wrapping of the guidewires can be highly problematic as the device cannot then be readily advanced over the guidewires.